the posterior section of the developing metencephalon recognized transiently within the vertebrate embryo; the rhombic lip extends posteriorly from the roof of the fourth ventricle to dorsal neuroepithelial cell and can be divided into eight structural units based on rhombomeres 1-8 (r1-r8), recognized at early stages of hindbrain development; producing granule cells and five brainstem nuclei, the rhombic lip plays an important role in developing a complex cerebellar neural system [ http://www.informatics.jax.org/accession/anna ]